// examine every valid move, trying to maximize Player.One's score
private int Max(GameBoard board, int depth, int alpha, int beta, ref int move)
{
// have we recursed far enough?
if (depth <= 0)
{
return Evaluate(board);
}
for (int index = 0; index < board.ValidMoves.Count; index++)
{
// report status if we're at top-most recursion depth
if (depth == Depth)
{
m_Status = (double)index / (double)board.ValidMoves.Count;
}
// copy current board
GameBoard board2 = new GameBoard(board);
// make move based on ValidMoves[index]
board2.MakeMove(index);
// get best move that opponent can make
int val = Min(board2, depth - 1, alpha, beta, ref move);
if (val >= beta)
{
// already found a better branch than this can possibly be
return beta;
}
if (val > alpha)
{
// found a better score!
alpha = val;
if (depth == Depth)
{
// udpate move if this is top-level
move = index;
}
}
}
// return best score found
return alpha;
}
// examine every valid move, trying to maximize Player.One's score
private int Max(GameBoard board, int depth, ref int move)
{
// have we recursed far enough?
if (depth <= 0)
{
return Evaluate(board);
}
// start with rediculously low score so that first
// inspection will result in a match
int score = int.MinValue;
// for each ValidMove ...
for (int index = 0; index < board.ValidMoves.Count; index++)
{
// report status if we're at top-most recursion depth
if (depth == Depth)
{
m_Status = (double)index / (double)board.ValidMoves.Count;
}
// copy current board
GameBoard board2 = new GameBoard(board);
// make move based on ValidMoves[index]
board2.MakeMove(index);
// get best move that opponent can make
int val = Min(board2, depth - 1, ref move);
if (val > score)
{
// found a better score!
score = val;
if (depth == Depth)
{
// udpate move if this is top-level
move = index;
}
}
}
// return best score found
return score;
}
protected int FindBestMove(GameBoard board, bool isPlayerOne, int score)
{
// assume first move is the best
int move = 0;
// scan valid moves, looking for best score
for (int index = 0; index < board.ValidMoves.Count; index++)
{
// create copy of current board to play with
GameBoard board2 = new GameBoard(board);
// make the next valid move
board2.MakeMove(index);
// what's the score?
int val = Evaluate(board2);
// best score for player one is positive,
// best score for player two is negative
if (isPlayerOne)
{
if (val > score)
{
score = val;
move = index;
}
}
else
{
if (val < score)
{
score = val;
move = index;
}
}
}
// report findings to the caller
return move;
}